Balanced gear pump



Aug. '27,` i940. .A. s. T. vRoLlx 2,212,994

BALANCED GEAR PUMP Filed Jan. 21, 1958. 5 Sheets-Sheet 1` /N @l MW v" m Q KNW Ns@ A @.k

Aug. '3? i940. A. s. T. vRoLlx BALANCED GEAR PUMP Filed Jan. 21, 1938 5 Sheets-Sheet 2 Aug. 27, I1940. A. s. T. vRoLlx '2,212,994

BALANCED GEAR PUMP Filed Jan. L21. 19138 5 shuts-'sheet 3 Aug. 27, 1940. A. s. T. vRoLux y 2,212,994

BALANCED GEAR PUMP Filed Jan. 21. 193s 5 sheets-sheet '4 27, 1940. A. s. T. vRoLlx 2,212,994

BALANCED GEAR PUMP Filed Jan. 21. 1938 5 Sheets-Sheet 5 Patented Aug. 27, 1940 PATENT lOFFICE BALANCED GEAR PUMP Albert Sylvain Toussaint Vrolix, Paris, France, assignor of one-half to Socit Anonyme LOutllage R. B. V., Paris, France Application January 21, 1938, Serial No. 186,197 In France May 22, 1937 3 Claims. (l. 10S-126) The present invention has for its object to improve the eiliciency of so-called gear pumps, which are also capable of operating as motors.

It is known that in these devices, the gears are subjected, under the effect of the pressure of the uid which passes through them, to considerable reactions which cause an excessive friction of the gears against the walls of their housings.

In order to compensate these detrimental reactions, various devices have already been proposed or applied: some of said devices make use of perfor-ations provided between the teeth of the gears themselves; others include balancing chambers lodged@ in the pump body and diametrally opposite the suction and delivery chambers.

In these latter devices, however, it is observed that the reaction produced by the thrust of the fluid in the zone of mesh of each gear is not compensated. Now the pressure ofthe fluid in this zone actually becomes very high since the iluid which is imprisoned between the teeth of the gears is taken from the delivery chamber, that is to 'say at an already very high pressure, in most cases. Furthermore, said pressure is pulsating, and not continuous, a fact which makes the drawbacks thereof more serious.

In other devices, in order to reduce the amount of iluid imprisoned on the pitch-arc, recesses are lprovided as close together as possible on the end walls facing the gears. However, the result of these artifices is to decrease the distance between the suction chamber and the delivery chamber, so that they frequently cause leaks. They cannot therefore be eilicient at the high pressures which are now required from such machines.

According to the present` invention, the balancing of these gear devices which are capable of operating as pumps or as motors is effected, without any perforations between the teeth, by the co-operation, for each gear, of two balancing chambers each embracing a different portion of the periphery of the gear and extending over arcs of unequal size, the simple or multiple chamber of greatest length being arranged diametrally opposite the gear arc which is subjected to the pressure produced or received (pump or motor) and the pitch-arc, the length of said chamber being approximately equal to the sum of said two arcs-with which it communicates-whereas the chamber of smallest length is diametrally opposite the gear arc which is-subjected to the suction (pump) or to the exhaust (motor), and communicates with said arc.

Said balancing chambers and the conduits which open therein are provided, either in the pump body itself in which the gears rotate, or again partially or totally in the walls which face the sides of said gears.

For the purpose of ensuring the balancing of. the pump or motor gear system` in both directions of operation, by eliminating any possibility of unbalancing at the instant when said directions are reversed, the invention also includes 10 embodiments in which, to each gear there is made to correspond, on the one hand two equal balancing notches or chambers which are respectively diametrally opposite the arcs subjected to the pressure and the suction and com- 15 municate with said arcs, and on the other hand a third chamber extending over an arc which is opposite and approximately equal to the pitcharc, the action-of said third chamber being automatically added, by means of a set of valves or 20 equivalent devices, to that of the balancing chamber which is under pressure, according to the direction of rotation of the gears.

As in the simplified embodiment, the balancing chambers and the conduits which supply them 25 may be provided either in the pump body, or in the end walls.

Branch conduits may be taken oi the conduits which supply the balancing chambers for the purpose of using a part of the fluid under 30 pressure for lubricating the bearings.

The principleoi the invention is illustrated by means of various embodiments, in the accompanying drawings in which:

Fig. 1 shows a diagrammatical view of a bal- 35 ancing device for a single direction of rotation; said device is lodged in the body of the bores' receiving the gears of the pump or motor (the gears are shown in transverse section).

Fig. 2 is a view in transverse section of asimilar device lodged in the end Walls.

Fig. 3 shows diagrammatically, in transverse section, a balancing device which is operative for both directions of rotation of the group of gears and is lodged in the body of the bores.

Fig.,4 is a diagrammatical view corresponding to the previous one, but in which the balancing vdevice is lodged in the end walls.

and 10. l

Fig. 6 is an axial sectional plan view of this same embodiment.

Fig. 7 is a view oi one of the end walls, corresponding to Figs. 5 and 6, said end wall being seen from the side facing the inside of the pump. v

The two end walls are identical and each accommodates a half of the balancing device.

Fig. 8 shows a view of an end wall, in section along the plane projected at lla-8a or 8b-8b in Fig. 5.

Fig. 9 shows a view of an end wall in transverse section: said section taken along the plane projected at 9-9 in Figs. 7 and 8.

Fig. 10 is a view of one of the end walls, seen from the side of said'end wall facing the outside of the pump, said end wall containing hall of the balancing device according to the invention.

Fig. 11 shows a perspective diagram of the balancing conduits of Figs. 4 to 10.

Referring to Fig. 1:

The gears 2 and 3 rotate inside bores provided in the pump body I. If, when the gears rotate in the direction f, the machine operates as a pump, the chambers 4 and 5 are respectively the suction and delivery chambers which are connected by unions 6 and 'I to the suction and delivery conduits.

According to the invention, the gear 2 is balanced by the co-operation of two balancing notches or chambers 9, I4 which are provided in the pump body I at the periphery of the gears and extend over arcs of unequal lengths.

The chamber 9 which corresponds to the largest arc, viz. is diametrically opposite the angle a corresponding to the part of the gear which is subjected, in the delivery chamber 5, to the pressure produced (operation as a pump), or received (operation as a motor) and to the part of the gear which receives the pressure resulting from the imprisonment of the fluid at the mesh points.

Said chamber 9 communicates, through the conduit 8, with the delivery chamber 5.

The chamber I4, which corresponds to the smallest arc, viz. l, is diametrally opposite the part of the gear which is subjected to the suction (pump) or to the exhaust (motor) and said chamber is connected, through a conduit I3, to the suction chamber 4.

Similarly, for'the gear 3, balancing chambers I0 and I5 having conduits, respectively 8 and I3 connecting same to the delivery chamber 5 and the suction chamber 4, are provided, symmetrically with respect to the previous ones, in the pump body I, at the periphery of the bore in which the gear 3 rotates.

The diagram of Fig. 2 shows an arrangement for balancing the gears which is similar to the previous one, but lodged in the end walls 22, 23 of the pump body and applied against the ends of the gears 2 and 3.

In this iigure the same references have been retained for the members which have already been described. The balancing chambers 9, I 0 (pressure) and I4, I5 (suction) are provided in each end wall 22 and 23.

In one of the end walls, the end wall 22, are provided the conduits 8, 8 through which the chambers 9 and I0 communicate with the delivery chamber 5.

In the other end wall, are provided the pipes I3, I3 through which the chambers Il, I5 communicate with the suction chamber 4.

The balancing chambers of the same name (pressure or suction), which are provided facing each other on the end walls, communicate freely with each other through the intermediary of the hollows of the gear teeth.

The devices shown diagrammatically in Figs. 1 and 2 are only capable of balancing the gears in one direction of rotation.

Fig. 3 shows a balancing device according to the invention and which is operative for both directions of rotation of the gears.

For each of the gears 2 and 3 are provided, as previously, balancing chambers 9, I4 and I0, I5 which are in this case lodged in the pump body but which correspond to equal arcs, one set of chambers being diametrally opposite the part of the gears on which the delivery pressure is exerted, the other set being diametrally opposite the part of the gears which is subjected to the suction.

Said balancing chambers 9, I4 and I0, I5 are connected as previously, by conduits 8 and I3, respectively to the delivery chamber 5 and the suction chamber 4.

In combination with said balancing chambers which extend over equal arcs, this embodiment includes, for each gear, a third chamber or notch 20, 2I, which is located between the other two chambers for each gear and extends over an arc which is approximately equal and opposite to the pitch-arc of the gears. Said third chamber (20 for the gear 2, 2| for the gear 3) is connected by conduits I9, I9n (I8, I8) to the conduits 8, I3, through valves respectively II and I6 (I2 and I7) either of which lift from their seats, in such a manner that this additional chamber 20, 2| is always in communication with the pressure side of the pump, as can be very clearly seen in Fig. 3.

The pressure angle at the mesh point, y, which always exists whatever be the direction of rota tion, is thus compensated for each of the gears, by an angle fyi, of exactly or approximately equal value, in the corresponding notch 20 or 2I the balancing pressure always exists whatever be the direction of operation.

A balancing device is thus obtained which is equivalent to that of Figs. 1 and 2, but which is operative in both directions of rotation of the gears of the pump.

In the case of Fig. 4, the same device is lodged in the end Walls 22, 23 which face the anks ol the gears.

As in the embodiment of Fig. 2, the balancing chambers of the same name are provided in each of the end walls and are made therein facing each other. Said chambers communicate freely with each other through the hollows of the teeth.

In this embodiment, one of the end walls, in this case 22, carries the conduits 8, I8, I 9 and the valves-in this case II, I2-which are operative for the balancing under pressure in the direction of rotation f. The other end wall, 23, carries the conduits I3, Isa, I9a and the valves I6, I1 which are operative for the balancing under pressure in the opposite direction to f, in such a manner that the chambers 20, 2I are both placed in communication with the pressure side of the pump, whatever be the direction of rotation.

40, 4I respectively designates ports opening into the delivery or the suction chamber for the operation as a pump in the direction f.

Figs. 5 to 11 show, by way of example and without being in any way limitative, an embodiment of a. balanced machine corresponding to the diagram of Fig. 4, the same reference numerals designating corresponding members.

In said figures:

22, 23 designate the end walls enclosing the Conduits 33, 34, which are connected togetherby a manifold conduit 38, ensure the axial re- ,leas'e of the system of gears 2, 3.

An outlet connection 52 is provided at the end of the manifold conduit 38.

In Fig. 6 blind holes 50, 5I are shown, for balancing the respective ports 40 and Il.

ATwo outer walls 36, 31 laterally enclose the machine, pump or motor.

It is, of course, understood that the principle of the radial balancing of gear pumps or motors, various applications of which have been described herein, can` be embodied in other constructional modiiications which are all within the scope of the invention.

I claim:

1. A device for balancing gear pumps which are also capable ofoperating as motors, comprising in combination with pump gears, two equal balancing chambers respectively located diametrally opposite the arcuate parts of each gear subjected to the pressure and to the suction, said two chambers communicating with said arcuate parts, and a third balancing chamber extending over an arc which is opposite and approximately equal to the pitch-arc of the gears,

and means whereby the balancing action of said third chamber is added automatically to the action of the one of the two rst balancing chambers which is connected to the pressure side of the pump according to the direction ot rotation of the gears of said pump.

2. A device for balancing gear pumps which are also capable of operating as motors, comprising in combination with pump gears, two equal balancing chambers respectively located diametrally opposite the arcuate parts of each gear ,subjected tothe pressure and to the suction, said chambers communicating with said arcuate parts, and a third balancing chamber extending over an arc which is opposite and approximately equal to the pitch-arc of the gears, and valves operating in such a manner that the action of the third balancing chamber is automatically added to the action of the one of the two rst balancing chambers which is connected to the pressureA side of the pump according to the direction of rotation of the gears of said pump. v

3. A device for balancing gear pumps which are likewise adapted to operate as motors comprising, in combination with each of the gears of these pumps, two systems of balancing chambers, each extending over a different part of the periphery of the corresponding gear and yoccupying arcs of unequal values, the system of greater area being diametrally opposite and approximately equal to the arc of the gear which is subjected to the pressure produced or received and 'to the arc of gear intermesh, while the system of smaller extent is diametrally opposite the arc of the gear subjected to the suction or to the exhaust, and means providing communications between said systems and the arcs to which they are respectively opposite.

ALBERT SYLVAIN TOUSSAINT VROLIX. 

